The tectonic evolution and new exploration results onhydrocarbon potential, cased study in the NE-Eastern part, Cuu Long basin,Vietnam continental shelf

Abstract

New exploration results proved the presence of Tertiary sedimentary basins with hydrocarbon potential in the boundaries of Vietnam continental shelf. These basins were perhaps formed in the Early Oligocene on the Mesozoic basement of continental crust and were filled with mainly deltaic clastic sediments. Since very early Miocene these basins have linked together and extended wider. Sediments of marine and prograding delta facies accumulated and widespreaded on the whole continental shelf. At the Middle Miocene to present-day the opening of the Bien Dong Sea (Vietnam East Sea), the regional tectonic subsidence and the eustatic fluctuation had created sedimentary formations of open and deep marine facies with turbidite shale, platform carbonate including reef build-up. Andesite and basalt extrusion occurred in form of dykes resulting from tectonic inversions in Late Oligocene, in the beginning of Middle Miocene, particularly in Late Miocene-Pliocene.

These Tertiary sedimentary basins are expected to have hydrocarbon potential and need to be investigated and explored adequately. The main risk is the drilling technology, the exploitation in the deep sea and high investment cost.

The recently exploration results in illustrated a better potential in Lower Oligocene reservoir in South East margin of Cuu Long basin and many new signs. These signs need to be highlight researched for predicting accumulation distribution in study area, in purpose of oil and gas exploration for next stages.